The present invention relates to image data storage systems. More particularly, the invention relates to an image data storage system in which binary (black and white) or multi-valued (shaded image) image data is stored in a memory of relatively small capacity and in which data can be easily inputted, outputted and edited.
Heretofore, an image data storage system has been employed in which image data outputted serially (element by element) from a sensor array by electronically scanning the array in a main scanning direction is stored directly. In another known system, an image data for one line or a plurality of lines in the main scanning direction is stored in advance, and thereafter the stored data is compressed one-dimensionally prior to storage. The former system in which the image data is stored directly suffers from a drawback in that the required memory capacity is relatively large. On the other hand, the latter system, for example, as shown in U.S. Pat. No. 4,383,296, issued to Sander, in which the data is compressed one dimensionally is advantageous with regard to storage capacity and in the case where the data is to be communicated externally, but is disadvantageous in that it is rather difficult to use in editing pictures. The term "editing" as used here means that parts of a picture are moved or overlapped, or an image is rotated, or reduced or enlarged.
Accordingly, an object of the invention is to provide an image data storage system in which image data can be stored in a memory of relatively small capacity and the data can be easily edited.
Another object of the invention is to provide an image data storage system in which editing functions wherein parts of an image are moved or overlapped, or an image is rotated, reduced, or enlarged, can be performed with high speed and independently of parts of the image.